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1、大連理工大學(xué)碩士學(xué)位論文船用中厚鋼板激光彎曲成形過程數(shù)值模擬姓名：裴繼斌申請學(xué)位級別：碩士專業(yè)：材料學(xué)指導(dǎo)教師：張立文20020601船用中厚鋼板激光彎曲成形過程數(shù)值模擬摘要板材激光彎曲成形技術(shù)是利用激光束掃描金屬板材時(shí)產(chǎn)生的熱應(yīng)力使板材成形的新工藝，在汽車、造船和航空等領(lǐng)域具有廣闊的應(yīng)用前景。激光束掃描板材時(shí)，在照射區(qū)域和鄰近區(qū)域產(chǎn)生強(qiáng)烈的溫度梯度，使材料產(chǎn)生非均勻的熱應(yīng)力分布，當(dāng)熱應(yīng)力超過材料的屈服點(diǎn)時(shí)，材料發(fā)生塑性變形。本文使用有限元軟件MSC．Marc對板材激光彎曲成形過程進(jìn)行數(shù)值模擬。綜合考慮材料的熱物性和力學(xué)性能隨溫度的變化等因素，建立了三維熱力
2、耦合模型分析船用中厚鋼板激光彎曲成形過程，計(jì)算成形過程的溫度和應(yīng)力應(yīng)變，并預(yù)測鋼板最后的彎曲角度。為了驗(yàn)證數(shù)值模擬結(jié)果，對船用中厚鋼板激光彎曲成形過程進(jìn)行了實(shí)驗(yàn)研究。分別選用不同厚度、不同掃描速度和不同激光功率對金屬板材激光彎曲成形進(jìn)行參數(shù)研究，對溫度和彎曲角度的變化進(jìn)行實(shí)時(shí)測量。彎曲角度受材料力學(xué)性能、熱物性以及工藝參數(shù)等因素的影響，隨激光束掃描次數(shù)的增加而增大，是激光功率和掃描速度的函數(shù)。模擬結(jié)果與實(shí)驗(yàn)結(jié)果符合較好，從而驗(yàn)證了模型的適用性。關(guān)鍵詞：激光彎曲成形：熱應(yīng)力；金屬板材；數(shù)值模擬；有限元船用中厚鋼板激光彎曲成形過程數(shù)值模擬AbstractLase
3、rformingisapromisingtechnologyinmanufacturing，suchasintheautomobile，shipbuilding．a(chǎn)ndaerospaceindustries．Theprocessutilizesthethermalstressinducedbylaserirradiationtoformsheetmetalintodifferentshapes．Thelocalnatureoflaserirradiationyieldshightemperaturegradientsbetweentheirradiateds
4、urfaceandtheneighboringmaterial，Thetemperaturedistributionmakesthematerialtoexpandnon—uniformly．thusleadingtonon-uniformthermalstressesWhenthethermalstressesexceedtheyieldpointofthematerial，thematerialdeformsplastically．Thelaserformingprocesshasbeensimulatednumerically．Fortheanalys
5、is，thefiniteelementcode‘MSC．Marc’isused．A3·DFEMsimulationhasbeencarriedout，whichincludesacoupledthermal-structuralanalysisaccountingforthetemperaturedependencyofthethermalandmechanicalpropertiesofthematerials．Theproposedmodeliscapableofcalculatingthetime-dependenttemperatures，stres
6、sesandstrainsduringthelaserformingprocess．Itcanalsopredictthefinalbendingangleofshipbuildingplates．Anexperimentwascarriedouttovalidthenumericalsimulation．Thesheetmetalofdifferentthicknesshadbeenperformedfordifferentscanningspeedsandlaserpowers．Themeasurementofreal—timetemperaturean
7、dbendinganglewascarriedout．Thebendingangleisaffectedbythemechanicalandthermalpropertiesofthesheetmetalmaterial，theprocessingparameters，andtheoutputoflaserenergy．ThebendingangleisincreasedwiththenumberoflaserbeamscanningpassesandiSthefunctionofthe1aserpowerandthelaserbeamscanningspe
8、ed．Thesimulationresultsare
